Freiburger historische Bestände - digital

132

Cunningham Memoirs.

to the centre of the long band, and in such a way that the free extremity
of the former could be approximated towards or carried away from either
end of the latter. When the measurement had to be conducted on the
brain in situ a thread was tied horizontally round the head so as to pass
round the most projecting point of the frontal and the most prominent
point of the occipital lobe. This constituted the base line, and the long
band of the instrument was then placed at right angles to this line, and
moved until the joint between the two limbs came to lie immediately
under the Sylvian Point. It was then bent round the head, and secured
in this position while the short metal band was moved upwards and downwards
, until its upper border was found to coincide with the general
direction of the Sylvian fissure.

In dealing with hemispheres which were removed from the cranial
cavity a different plan was pursued. A rectangular sheet of glass, 18
inches long and 6 inches wide, was bisected by two straight lines cut by

Fig. 32.—Method of ascertaining the angle of the Fissure of Sylvius in a cerebral hemisphere

removed from the cranial cavity.

a diamond, first in the longitudinal direction and then in the transverse
direction. These lines intersected each other at right angles. The
cerebral hemisphere was placed with its mesial surface in contact with the
glass. It was then carefully adjusted, so that the longitudinal line
accurately corresponded with its longest antero-posterior diameter, while
the transverse line intersected the Sylvian Point. The metal instrument
was applied to the brain, as before—the long limb being bent round